Electrical safety in opencast mining

Excavators

High performance with stable and reliable monitoring

The big excavators used for open-cast mining have lots of different drives. They use both medium voltage engines and low voltage drives. The large drives, in particular, are normally supplied by ungrounded systems. These are monitored by an ISOMETER® with a coupling device. For smaller drives, we recommend monitoring with RCMS residual current monitoring systems or ISOMETER® insulation monitoring with EDS, as in both cases the faults occurring are immediately detected and reported to significantly improve availability.

Conveyor belts

Getting from A to B quickly but safely

Electric motors are generally employed for conveyor belts used in mining, which are driven by soft starters or frequency converters. However, these generate critical harmonic vibrations and DC currents which would normally not be present in the feeding AC system. With regular GFCI or simple insulation monitors (e.g. 3 lamp method or 2 voltmeter process), this cannot be monitored with the requisite precision. There is a need for modern monitoring equipment which can recognize and report these problems quickly. Some standards even require a quick shutdown, which can be achieved via ground-fault monitoring devices.

Primary crushers, crushers

From big to small and smaller - safely

Primary crushers and crushers are needed in mining to break down the stone extracted from the ground. These use very large, powerful motors which are powered by soft starters or frequency converters due to their size. The resulting harmonic vibrations and DC currents are not recognized by normal GFCIs. The use of a freely adjustable RCMA residual current monitoring system (ground-fault monitor) is therefore advisable. It guarantees fault detection.

EN 61557-15Electrical safety in low voltage distribution systems up to 1000 V ac and 1500 V dc - Equipment for testing, measuring or monitoring of protective measures - Part 15: Functional safety requirements for insulation monitoring devices in IT systems and equipment for insulation fault location in IT systems

DIN EN 50178Electronic equipment for use in power installations

Main and sub-distribution boards

A safe power supply is essential

The power supply is decisively important when it comes to operating mines. The medium voltage fed in is transformed down to 400 V in the transformer stations and fed to the mine via cable bars or busbars and the low-voltage distribution boards and sub-distribution boards. Bender ISOMETER®s or RCMS residual current monitoring systems (ground-fault monitors) monitor this and ensure continuous operation. Power quality is the perfect solution for monitoring the main and the sub-distribution boards.